U.S. patent number 5,019,606 [Application Number 07/374,467] was granted by the patent office on 1991-05-28 for aqueous solutions of polyamidoamine-epichlorohydrin resins, and preparation and use thereof.
This patent grant is currently assigned to Hoechst AG. Invention is credited to Walter Kamutzki, Manfred Marten.
United States Patent |
5,019,606 |
Marten , et al. |
May 28, 1991 |
Aqueous solutions of polyamidoamine-epichlorohydrin resins, and
preparation and use thereof
Abstract
Aqueous solutions of polyamidoamine-epichlorohydrin resins and
preparation and use thereof. A stable aqueous resin solution having
a pH of not more than 7 and containing as the resin a
water-thinnable polyamidoamine-epichlorohydrin resin (A) obtained
by reaction of a water-thinnable basic polyamidoamine (B)
comprising an acid component (B.sub.1) and an amine component
(B.sub.2) with epichlorohydrin (C), the level of organically bound
chlorine in the resin (A) being not more than 4% by weight. The
present invention further relates to a process for preparing these
products and to the use thereof in particular for increasing the
wet strength of paper.
Inventors: |
Marten; Manfred (Mainz,
DE), Kamutzki; Walter (Dieburg, DE) |
Assignee: |
Hoechst AG (DE)
|
Family
ID: |
6357862 |
Appl.
No.: |
07/374,467 |
Filed: |
June 30, 1989 |
Foreign Application Priority Data
Current U.S.
Class: |
523/414; 523/417;
523/416; 523/418 |
Current CPC
Class: |
D21H
21/20 (20130101); D21H 17/55 (20130101) |
Current International
Class: |
D21H
21/14 (20060101); D21H 17/00 (20060101); D21H
17/55 (20060101); D21H 21/20 (20060101); C08K
063/00 () |
Field of
Search: |
;523/416,417,418,414,420
;524/538 ;528/341 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Michl; Paul R.
Assistant Examiner: Rogers; Christopher P.
Attorney, Agent or Firm: Bierman and Muserlian
Claims
We claim:
1. A process for preparing a stable aqueous resin solution having a
pH of not move than 7 and containing as the resin a water-thinnable
polyamidoamine-epichlorohydrin resin (A), which comprises reacting
watersoluble basic polyamidoamines (B) with epichlorohydrin (C)
molar ratio of 0.6 to 2 in an aqueous system and then, optionally
after a prior acidification of the reaction system, reacting with a
sufficient amount of the base (D) at 25.degree. to 95.degree. C. so
that the pH is greater than 8, and subsequently adjusting the pH to
not more than 7 by addition of acid.
2. The process as claimed in claim 1, wherein the amount of base is
0.1 to 0.6 mole per mole of epichlorohydrin used.
3. The process as claimed in claim 1, wherein the base used is
sodium hydroxide or potassium hydroxide.
4. The process as claimed in claim 1, wherein the pH is brought to
a pH of 1.5 to 5 with an acid.
5. The process as claimed in claim 4, wherein the acid used is
sulfuric acid, hydrochloric acid, acetic acid or formic acid.
6. The process as claimed in claim 1, wherein the reaction with
base (D) takes place at 40.degree. to 70.degree. C.
Description
DE Auslegeschrift No. 1,177,824 discloses reacting polyamines which
have three or more amino groups with C.sub.3 -C.sub.10
-dicarboxylic acids and converting the resulting polyamides with
epichlorohydrin into water-soluble condensation products. For the
conversion, the epichlorohydrin can be used in a molar ratio of
from about (0.5 to 1.8):1 to the secondary amino groups of the
polyamide. The products obtained can be used for improving the wet
strength of paper.
It is also known (for example from British Pat. No. 865,727) that
such aqueous condensation products from polyamidoamines and
epichlorohydrin contain inter alia chlorohydrin structural units of
the formula ##STR1## Consequently, polyamidoamine-epichlorohydrin
resins can contain an appreciable amount of organically bound
chlorine. However, environmental protection legislation now
requires that products must not own more than the minimal
organically bound chlorine content.
U.S. Pat. No. 3,352,833 describes inter alia an alkaline
aftertreatment of polyamidoamine-epichlorohydrin resins for
reactivating the wet strength activity, where the acidified resin
solutions are made to react with 0.25 to 2.5 equivalents of base
per equivalent of acid in an aqueous solution. According to Example
10 of said U.S. Pat. No. 3,352,833, the base is added before the
resin is used for papermaking, and the resin solution is aged for
four hours and then used at once. There is no mention of the
degradation of the organically bound chlorine in these
publications. However, repeating the alkaline aftertreatment
specified in this U.S. patent shows that it does not produce
sufficiently stable and/or sufficiently low-chlorine resin
solutions (cf. the comparative tests below). A further disadvantage
of this alkali activation prior to processing, for example in the
paper stock, is the addition of equipment required by this method,
such as vessels, stirrers and metering means. For the optimal use
of the polyamidoamine-epichlorohydrin resins to be activated under
alkaline conditions it is also necessary to meter the added alkali
exactly, to adhere to certain aging times, and, owing to a
reduction in the stability of the alkaline solution which occurs,
to use this solution within a certain time.
The present invention now provides a stable aqueous resin solution
having a pH of not more than 7 and containing as the resin a
water-thinnable, preferably water-soluble
polyamidoamine-epichlorohydrin resin (A) obtained by reaction of a
water-thinnable, preferably water-soluble, basic polyamidoamine
(B), comprising an acid component (B.sub.1) and an amine component
(B.sub.2), with epichlorohydrin (C), the level of organically bound
chlorine in the resin (A) being not more than 4% by weight.
The present invention further provides a process for preparing
these resin solutions and the use thereof.
The attribute "stable" is here intended to mean that during a
storage period of at least three months at room temperature (or at
least 10 days at 50.degree. C.) there is no sign of gelling or
precipitation.
The term "solution" here is also intended to include a colloidal
solution.
The pH of the resin solution according to the invention is
preferably between 1.5 and 5. The viscosity of a 12.5% solution at
25.degree. C. is in general about 10 to 200, preferably 15 to 80,
mPa.s.
The level of resin (A) in the solution according to the invention
is in general between 8 and 25% by weight, preferably 10 and 15% by
weight, based on the solution.
In addition, this resin solution contains small amounts of
inorganic substances (from the base treatment and the subsequent
neutralization) and optionally up to 0.5% by weight, preferably
0.05 to 0.2% by weight, of fungicides, such as sorbic acid or
potassium sorbate, and further optional additives, for example
antifoams.
Resin (A) has in general an average molecular weight M.sub.n of at
least 500, preferably of at least 1,000, in particular of 1,000 to
500,000. The level of organically bound chlorine is in general
between 0.1 and 4, preferably between 1 and 4, in particular
between 1 and 3, % by weight. In a 12.5% strength resin solution
this chlorine content does not exceed values of 0.5% by weight and
is in general between 0.0125 and 0.5, preferably between 0.125 and
0.5, in particular between 0.125 and 0.375, % by weight, based on
the solution.
The amount of units in (A) derived from epichlorohydrin is in
general 20 to 50% by weight, preferably 30 to 40% by weight, based
on (A).
The novel process for preparing above-described resin solutions
comprises reacting water-soluble basic polyamidoamines (B) with
epichlorohydrin (C) in a ratio of 0.6 to 2 moles per mole of basic
amino groups of polyamidoamine (B) in an aqueous system and then,
if necessary after prior acidification of the reaction system,
reacting with a sufficient amount of a base (D), in general 0.1 to
1.0 mole, preferably 0.1 to 0.6 mole, per mole of epichlorohydrin
used at 25 to 95.degree. C. that the pH is greater than 8, and
subsequently adjusting the pH by addition of acid to not more than
7.
The water-soluble polyamidoamine (B) has in general an average
molecular weight M.sub.n (determined via the carboxyl end groups,
of at least 500, preferably at least 1,000 and in particular 2,000
to 20,000; the amine number is usually between 200 and 400,
preferably between 250 and 350, mg of KOH/g, and the acid number
between 0 and 50, preferably between 10 and 30, mg of KOH/g.
Polyamidoamines (B) which meet the conditions according to the
invention are described for example in DE-B-No. 1,777,824, GB Pat.
No. 865,727, U.S. Pat. Nos. 4,075,177 and 4,336,835, DE-A-No.
3,323,732 and EP-A-No. 31,899, which are hereby incorporated herein
by reference. Of the products mentioned, it is the products
described in DE-A-No. 3,323,732 which are preferred, provided they
fall within the present scope.
In general, such polyamidoamines (B) are obtained by reacting the
acid component (B.sub.1), such as dicarboxylic acids or functional
derivatives thereof or .omega.-aminocarboxylic acids or lactams
thereof, with the amine component (B.sub.2), such as polyamines.
Preferably this component (B.sub.2) comprises a mixture of
polyamines and alkanolmonoamines if the acid component (B.sub.1) is
an aliphatic or aromatic carboxylic acid or a functional derivative
thereof, with or without an aminocarboxylic acid or a lactam
thereof. The abovementioned polyamines contain two or more primary
amino groups and preferably one or more secondary or tertiary amino
groups. The mixing ratio of these components has to be chosen in
such a way that the resulting polyamidoamine (B) still has a
sufficient number of basic (i.e. reactive with epichlorohydrin (C))
amino groups, no gelling occurs in the course of the reaction and
the molecular weight of (A) is within the stated range.
The polyamidoamines (B) are for example reaction products of
(a) saturated or olefinically unsaturated aliphatic C.sub.3
-C.sub.10 -dicarboxylic acids or functional derivatives thereof or
.omega.-aminocarboxylic acids of 3 or more carbon atoms or lactams
thereof with
(b1) aliphatic polyamines which contain two or more primary and one
or more further, secondary and/or tertiary amino groups, or
(b2) a mixture of polyamines (b1) with
(c1) polyamines which contain one or more primary and, optionally,
one or more secondary amino groups and do not fall within
definition (b1), the additional polyamines being used in such
amounts that their contribution of primary amino groups, based on
the total amount of primary amino groups, does not exceed 70%,
preferably 50%, and in particular 30%, and/or
(c2) alkanolmonoamines of 2 to 20 carbon atoms, preferably 2 to 6
carbon atoms, and 1 to 3, preferably 1 or 2, OH groups, in
particular one OH group. Preferably, these alkanolmonoamines have
the formula (II) indicated hereinafter.
Suitable water-soluble polyamidoamines (B) are in particular:
Reaction products of (a) saturated aliphatic C.sub.3 -C.sub.10
-dicarboxylic acids, such as succinic acid, glutaric acid, adipic
acid, sebacic acid, malonic acid or functional derivatives thereof,
such as anhydrides and esters, the first three acids being
preferred, with the polyamines mentioned above under
(b.sub.1)/(c.sub.1), preferably from a mixture with
alkanolmonoamines.
2. Reaction products of those saturated modified dicarboxylic acids
or derivatives thereof, which are obtained by addition of
aliphatic, cycloaliphatic, araliphatic or heterocyclic polyamines
with two or more primary and/or secondary amino groups onto
.alpha.,.beta.-olefinically unsaturated carboxylic esters whose
alcohol radical has 1 to 8, preferably 1 to 3, carbon atoms, such
as ethyl acrylate or methyl methacrylate, and are then reacted with
the polyamines mentioned above under (b.sub.1)/(c.sub.1) or
mixtures thereof, preferably mixtures with alkanolmonoamines.
3. Reaction products of .omega.-aminocarboxylic acids containing
three or more carbon atoms or lactams thereof, for example
6-aminocaproic acid and 8-aminocaprylic acid or 6-caprolactam and
8-capryllactam, with the (b.sub.1)/(c.sub.1) polyamines or mixtures
thereof, preferably with alkanolmonoamines.
4. Reaction products of olefinically unsaturated dicarboxylic
acids, such as maleic acid or fumaric acid, or functional
derivatives thereof, such as anhydrides or esters, with the
polyamines mentioned above under (b.sub.1)/c.sub.1), or mixtures
thereof, preferably with alkanolmonoamines.
5. Those reaction products which are based not only on the
saturated aliphatic C.sub.3 -C.sub.10 -dicarboxylic acids mentioned
under 1. and the unsaturated dicarboxylic acids mentioned under 4.
but also on .omega.-aminocarboxylic acids or lactams thereof of the
type mentioned under 3. and not only on the polyamines mentioned
under (b1) but also on aliphatic, cycloaliphatic, araliphatic or
heterocyclic polyamines which contain at least one primary and
optionally a secondary amino group, i.e. for example a primary or a
secondary amino group, and alkanolamines. Preference is given to
those polyamidoamines which are based not only on the polyamines
mentioned above under (b.sub.1)/c.sub.1) or mixtures thereof,
preferably with alkanolmonoamines, and not only on the saturated
C.sub.3 -C.sub.10 -dicarboxylic acids but also on
.omega.-aminocarboxylic acids or lactams thereof of the type
mentioned under 3.
Reaction products of type (1) using diethylenetriamine,
triethylenetetramine and tetraethylenepentamine as polyamine and
2-aminoethanol as alkanolmonoamine are particularly preferred.
Suitable polyamines (b1) and (c1) are for example those of the
formula (I) ##STR2## where p is zero or an integer from 1 to 6,
preferably 1 to 4,
R.sub.1 is a divalent, preferably nonaromatic hydrocarbon radical
of 2 to 18 carbon atoms, preferably a branched or unbranched
alkylene radical of 2 to 10 carbon atoms, in particular 2 to 6
carbon atoms, or a cycloalkylene radical of 5 to 12 carbon atoms
and preferably 6 to 10 carbon atoms, or an aralkylene radical of 7
to 12 carbon atoms, preferably 8 to 10 carbon atoms,
R.sub.2 and R.sub.2' are independently of each other H or one of
the two radicals is ##STR3## where R is as defined above, and
R.sub.3 and R.sub.4 are independently of each other H or (C.sub.1
-C.sub.20)alkyl, preferably (C.sub.1 --C.sub.6)alkyl, which alkyl
radicals may also carry hydroxyl groups.
Examples of polyamines (b1) are: methylbis(3-aminopropyl)amine,
ethylbis(3-aminopropyl)amine,
N(3-aminopropyl)tetramethylenediamine,
N,N'-bis(3-aminopropyl)tetramethylenediamine,
polyalkylenepolyamines, such as dipropylene(1,2)triamine,
bis(3-aminopropyl)amine, tripropylene(1,2)tetramine and in
particular diethylenetriamine, triethylenetetramine and
tetraethylenepentamine.
Polyamines (c1) are for example: ethylenediamine, propylenediamine,
1-amino-3-methylaminopropane, 2-methylpentamethylenediamine,
pentaethylenediamine, hexamethylenediamine,
trimethylhexamethylenediamine, neopentyldiamine,
octamethylenediamine, dioxadodecanediamine, cycloaliphatic diamines
such as 1,2-, 1,3- or 1,4-cyclohexanediamine;
4,4'-methylene-bis-cyclohexylamine, isophoronediamine,
menthanediamine, 4,4'-diamino3,3'-dimethyldicyclohexylmethane,
3-aminomethyl-1-(3-aminopropyl-1-methyl)-4-methylcyclohexane,
N-methylethylenediamine, N-aminoethylpiperazine and
1,3-bis-aminomethylbenzene.
Suitable alkanolmonoamines are for example those of formula
where R.sub.1 is as defined above, such as 2-aminoethanol,
1-amino-2-propanol, 3-amino-1-propanol, 2-amino-1-butanol,
4-amino-1-butanol, 5-amino-1-pentanol, 6-amino-1-hexanol and
isomers thereof whose hydrocarbon radical is branched or which
carry the amino group and/or the hydroxyl group on a primary or
secondary carbon atom, and those which are derived from cyclic
hydrocarbon radicals, preferably of 5-7 carbon atoms.
The mixing ratios between the components in question which must be
maintained to obtain water-soluble polyamidoamines (B) having
optimal properties are easily determinable by preliminary
experiments. In general, the molar amount of dicarboxylic acid or
functional derivatives thereof to polyamine/alkanolmonoamine is
such that the ratio of carboxyl groups to the sum of primary
NH.sub.2 groups is 1: (0.8-1.4), preferably 1: (0.95-1.1). In the
case of mixtures of polyamines and alkanolmonoamines the ratio of
their molar amounts is 0.6:0.4 to 0.99:0.01, preferably 0.8:0.2 to
0.95:0.05.
The polyamidoamines (B) can be prepared in a conventional manner,
for example by heating the corresponding components at temperatures
of 125.degree. to 250.degree. C., preferably 140.degree. to
180.degree. C., for several hours in the absence of oxygen,
initially under atmospheric pressure and then under reduced
pressure, in the presence of a small amount of hydrazine hydrate or
hydrazides added if desired to avoid the darkening of the
polyamides. The reaction time depends on the temperatures and
pressures employed and is in general between 4 and 10 hours.
In place of the epichlorohydrin (C) it is also possible to use if
desired the dichlorohydrin (1,3-dichloro-2-hydroxypropane).
Suitable bases (D) are inter alia: alkali metal hydroxides,
preferably sodium hydroxide or potassium hydroxide, carbonates,
bicarbonates, alkaline earth metal hydroxides, such as calcium
hydroxide, and also benzyltrimethylammonium hydroxide,
tetramethylammonium hydroxide, tetraethylammonium hydroxide or
mixtures thereof.
The reaction products can be prepared by the process of the
invention by reacting the polyamidoamines (B) and epichlorohydrin
(C) in a first reaction step at a concentration of the reactants of
about 25 to 50%, preferably 35 to 45%, and at a temperature of
between 25.degree. 95.degree. C., preferably 40.degree. to
70.degree. C., until the viscosity of a 40% strength solution
(determined at 25.degree. C.) is about 100 to 600, preferably 200
to 400, mPa.s. Thereafter this solution is reacted in a second
reaction step with an aqueous solution of a base (D) present in an
amount of in general 0.1 to 1.0, preferably 0.1 to 0.6, mole per
mole of epichlorohydrin (C) used at a concentration of reactants of
10 to 40%, preferably 15 to 25%, and at a temperature of between
25.degree. and 95.degree. C., preferably 40.degree. to 70.degree.
C., until the viscosity of a 12.5% strength solution (determined at
25.degree. C.) is 10-200 mPa.s, preferably 15 to 80 mPa.s. The pH
in the second reaction step is greater than 8, preferably between 9
and 12. Thereafter the mixture has advantageously added to it, to
terminate the action and to stabilize the inherently
self-crosslinking reaction products, sufficient acid or acid
derivatives that the pH of the aqueous solution is 1 to 7,
preferably between 1.5 and 5, and the solids content of the
reaction solution is adjusted to 8-25% by weight by dilution with
water.
In another, less preferred embodiment, acid can be initially added
to the solution during or after the reaction of polyamidoamine (B)
and epichlorohydrin (C) to adjust the pH to less than 7, preferably
1.5 to 5. This acid reaction mixture is then admixed with
sufficient base (D) so that the pH is greater than 8, preferably
between 9 and 12, and this system is then maintained at a
temperature of 25.degree. to 95.degree. C., preferably 40.degree.
to 70.degree. C., for a period of 0.5 to 8 hours, preferably 1 to 4
hours.
Possible acids are in particular halogen-free acids, such as
sulfuric, phosphoric or acetic acid, and suitable acid derivatives
are corresponding anhydrides or acidic salts.
The amount of epichlorohydrin (C) is in general 0.6 to 2 moles,
preferably 1.0 to 1.4 moles, per mole of basic amino groups
(primary, secondary or tertiary) in polyamidoamine (B), and the
amount of base (D) is 0.1 to 1.0 mole, preferably 0.1 to 0.6 mole,
per mole of epichlorohydrin used.
The resins or resin solutions according to the invention have an
appreciably lower organically bound chlorine content than the prior
reaction products from polyamidoamine and epichlorohydrin and
therefore are highly suitable for significantly reducing the
organic chlorine content of waste waters, inter alia from paper
factories. This useful property is not possessed to the same extent
by the reaction products hitherto used for improving the wet
strength of paper. Owing to the long shelf life of the resin
solutions according to the invention, their wet strength activity
is constant even after months of storage.
By means of the reaction products prepared by the process according
to the invention it is possible to obtain excellent improvements in
the wet strength of paper --including paper made of unbleached
pulp. In some cases it is also possible, depending on the type of
paper or if desired, to increase the absorbancy. It is to be noted
that the reaction products virtually do not impair the whiteness of
paper made from bleached pulp. It may further be mentioned that the
rate at which the reaction products to be used according to the
invention undergo crosslinking on the paper or in the cellulose is
high and that the reaction products can also be used as retention
aids for fillers used in papermaking, as drainage aids for
improving the rate of paper formation, and as flocculants for
removing fine particles from dirty water, for example industrial
waste water.
To increase the wet strength of paper in accordance with the
present invention, a possible procedure is for example to add the
resins in question in the form of aqueous solutions to the aqueous
suspension of the paper raw material even before the processing
into paper. The amounts of resin required for obtaining the desired
wet strength are determinable without difficulty by preliminary
experiments. In general, it is advisable to use 0.05 to 2,
preferably 0.1 to 1.6, parts by weight of solid resin per 100 parts
by weight of paper raw material, advantageously in the form of an
aqueous solution whose reaction product content is 8 to 25,
preferably 10 to 15, % by weight.
The Examples which follow are intended to illustrate the invention
in more detail. Percentages are by weight, unless otherwise stated.
The organic chlorine content was determined as the difference of
the chlorine content determined by the combustion method of
Wickbold (reference standards: DIN 53 188, section 13, and DIN 53
474, sections 5.5 and 6.3) and the ionic chlorine content.
EXAMPLES
1. Preparation of polyamidoamine (B)
392 g of diethylenetriamine (3.8 mol) and 24.4 g (0.4 mol) of
2-aminoethanol were introduced into a four-necked flask equipped
with a stirrer, a thermometer and a distillation apparatus, and 584
g of adipic acid (4 mol) were added over 30 minutes a little at a
time, so that the temperature did not rise above 100.degree. C. The
mixture was then heated to 150.degree. C. under nitrogen over 3
hours, maintained at that temperature for one hour and further
heated to 170.degree. C., while the water formed distilled over at
a uniform rate. After a holding time of about 2 hours the
condensate had an acid number of 20 mg of KOH/g and an amine number
of 251 mg of KOH/g. After the heating had been removed, the
polyamidoamine was diluted with 570 g of water. The solution had a
solids content of 59.8% (1 g, 1 hour, 125.degree. C.) and a
viscosity at 25.degree. C. of 1174 mPa.s.
2. Preparation of a polyamidoamine-epichlorohydrin resin
(Comparison)
(a) 322 g of the polyamidoamine intermediate solution of Example 1
(corresponding to 0.857 eq of NH) and 321 g of water were
introduced into a three-necked flask equipped with a stirrer, a
thermometer and a condenser, and 111 g of epichlorohydrin (1.20
mol) were added with stirring. The mixture was heated to
55-60.degree. C. in the course of 30 minutes and maintained at that
temperature. After 6 hours the Gardner viscosity was I.
(b) 352 g of water were added, heated to 60.degree.-65.degree. C.
and maintained at that temperature. After 3 hours the Gardner
viscosity was F. 1295 g of water in which 2.5 g of potassium
sorbate had been dissolved were then added, and the resin solution
was cooled. It was then brought to pH 3.70 with 14 g of 48%
strength sulfuric acid. The resin solution had a solids content of
12.6% (1 g, 1 hour, 100.degree. C.) and a viscosity at 25.degree.
C. of 21 mPa.s.
3. Preparation of a polyamidoamine-epichlorohydrin resin
(Comparison)
(a) 207 g of the polyamidoamine intermediate solution of Example 1
(corresponding to 0.552 eq. of NH) and 207 g of water were
introduced into a three-necked flask equipped with a stirrer, a
thermometer and a condenser, and 66.5 g of epichlorohydrin (0.72
mol) were added with stirring. The temperature was raised to
60.degree. C. in the course of 60 minutes and maintained at that
level. After 3 hours the Gardner viscosity was M.
(b) 578 g of water were added, and the temperature was raised to
65.degree. C. and maintained at that level. After 4 hours the
Gardner viscosity was F-G. 442 g of water in which 1.5 g of
potassium sorbate had been dissolved was then added, the resin
solution was cooled. It was then brought to pH 3.9 with 9.2 g of
48% strength sulfuric acid. The resin solution had a solids content
of 12.6% (1 g, 1 hour, 100.degree. C.) and a viscosity at
25.degree. C. of 47 mPa.s.
4. Preparation of a polyamidoamine-epichlorohydrin resin
(Comparison)
(a) Initially Example (2a)/(b) was repeated, but the dilution with
water in stage (b) was to about 20%. The resulting resin solution
had the following data:
______________________________________ Solids content (1 g, 1 h,
100.degree. C.) 19.7% pH 4.01 Viscosity 25.degree. C. 46.5 mPa.s
Stability 50.degree. C. >10 days Chlorine total calculated 2.84%
Chlorine ionic found 1.67%
______________________________________
200 g of this resin solution contained:
______________________________________ 4.7 g of epichlorohydrin
158.9 meq 0.793 g of H.sub.2 SO.sub.4 100% 16.2 meq
______________________________________
(b) In line with the teaching of claim 11 of U.S. Pat. No.
3,352,833, 200 ml of the resin solution described in (a) were
reacted at room temperature with 4.1 ml of 10 N NaOH (corresponding
to 2.5 equivalents of NaOH per equivalent of H.sub.2 SO.sub.4) for
4 hours. The results are shown in Table 2.
(c) The alkali treatment was carried out as described in section
(b), except that the alkali was used in an amount corresponding to
Example 10 of U.S. Pat. No. 3,352,833, namely 17.5 ml of 10N NaOH
per 200 g of resin solution (=equivalent to the total amount of
epichlorohydrin and H.sub.2 SO.sub.4). For the results, again see
Table 2.
5. Preparation of a polyamidoaminc-epichlorohydrin resin
(Comparison)
(a) Initially Example (3a)(/b) was repeated; the resulting resin
solution had the following data:
______________________________________ Solids content (1 g, 1 h,
100.degree. C.) 12.4% pH 3.99 Viscosity 25.degree. C. 33.9 mPa.s
Stability 50.degree. C. >10 days Chlorine total calculated 1.69%
Chlorine ionic found 1.07%
______________________________________
200 g of this resin solution contained:
______________________________________ 8.81 g of epichlorohydrin
95.2 meq 0.557 g of H.sub.2 SO.sub.4 100% 11.4 meq
______________________________________
(b) As in (4b), 200 g of the above resin solution were reacted with
2.85 ml of 10N NaOH (2.5 equivalents/equivalent of H.sub.2
SO.sub.4) at room temperature for 4 hours. Results see Table 2.
(c) As in Example (4c), 200 g of the above resin solution were
reacted with 10.7 ml of 10N NaOH (=equivalent to the total amount
of epichlorohydrin and H.sub.2 SO.sub.4). For the results, see
Table 2.
6. Preparation of a polyamidoamine-epichlorohydrin resin (According
to the invention)
(a) 207 g of the polyamidoamine intermediate solution of Example 1
(corresponding to 0.552 eq. of NH) and 207 g of water were
introduced into a three-necked flask equipped with a stirrer, a
thermometer and a condenser, and 66.5 g of epichlorohydrin (0.72
mol) were added with stirring. The temperature was raised to
60.degree. C. in the course of 45 minutes and maintained at that
level. After 3.5 hours the Gardner viscosity was N.
(b) 578 g of 1% strength sodium hydroxide solution were added, and
the mixture was heated to 65.degree. C. and maintained at that
temperature. After 3 hours the Gardner viscosity was E-F. 442 g of
water in which 1.5 g of potassium sorbate had been dissolved were
then added, and the resin solution was cooled and then brought to
pH 3.9 with 11.7 g of 48% strength sulfuric acid. The resin
solution had a solids content of 12.7% (1 g, 1 hour, 100.degree.
C.) and a viscosity at 25.degree. C. of 39 mPa.s.
PREPARATION OF FURTHER RESINS (A) BY THE METHOD OF EXAMPLE 6
The method of Example 6 was employed with varying amounts of sodium
hydroxide to prepare the following additional products:
7. In reaction step (b), 578 g of 1.5% strength sodium hydroxide
solution were added. Acidification was effected with 24.9 g of 48%
strength sulfuric acid to a pH 1.75. The resin solution obtained
had a solids content of 13.3% (1 g, 1 hour, 100.degree. C.) and a
viscosity at 25.degree. C. of 34 mPa.s.
8. In reaction step b), 578 g of 2.0% strength sodium hydroxide
solution were added. Acidification was effected with 37.5 g of 48%
strength sulfuric acid to a pH 1.75. The resin solution obtained
had a solids content of 13.5% (1 g, 1 hour, 100.degree. C.) and a
viscosity at 25.degree. C. of 40 mPa.s.
PAPER TREATMENT
To 2 kg of a suspension of 10 g of bleached sulfite cellulose
having a freeness of 42.degree. to 43.degree. Schopper-Riegler were
added with vigorous stirring the 12.5% strength aqueous resin
solutions of Examples 2, 3, 6, 7 and 8 in an amount of 1% of solid
resin on cellulose.
Following an absorption time of at least 2 minutes, a Schopper
sheet former was used to form two sheets of paper approximately 320
m.sup.2 in area with a basis weight of 100 g/m.sup.2, which were
heated at 100.degree. C. on a drying cylinder for 5 minutes and
postcured in a drying cabinet at 120.degree. C. for 10 minutes.
Following a conditioning time of 24 hours at 20.degree. C. and 65%
relative humidity, the wet strengths in Newton (N) were measured on
test strips of the paper in accordance with the test method of the
Cellulose Institute of the Darmstadt College of Technology. The
paper obtained in this manner had a wet strength considerably
higher than that of a paper produced from the same bleached sulfite
cellulose under the same experimental conditions without the
addition of the aqueous solutions of the products used according to
the invention.
The wet strengths in Newton (N) are given in relative %, based on
comparative product 2=100%, in Table 1.
TABLE 1
__________________________________________________________________________
Organically bound chlorine (%) Total chlorine Ionic based on based
on Wet strength Shelf life Example content (%) chlorine (%) resin
solution resin (A) activity (%) at 50.degree. C. in
__________________________________________________________________________
days 2 (comparison) 1.76 1.03 0.73 5.8 100 >10 3 (comparison)
1.69 1.10 0.59 4.7 100 >10 6 1.69 1.33 0.36 2.8 99 >10 7 1.69
1.40 0.29 2.2 100 >10 8 1.69 1.56 0.13 1.0 99 >10
__________________________________________________________________________
Table 1 shows that, compared with Comparative Examples 2 and 3, the
level of organically bound chlorine in Examples 6 to 8 is
distinctly reduced, in Example 8 the value being only about 20% of
that of Comparative Example 3. Moreover, the reaction products
prepared by the process according to the invention show excellent
wet strength activities and long shelf lives.
TABLE 2 ______________________________________ 4b 4c 5b 5c
______________________________________ Resin 4a 4a 5a 5a Resin
solution (g) 200 200 200 200 Total chlorine (%) 2.84 2.84 1.69 1.69
Cl.sup.- (%) 1.67 1.67 1.07 1.07 10 N NaOH ml 4.1 17.5 2.85 10.7 pH
9.9 12.7 10.5 12.5 Cl.sup.- after 1 h (%) 1.97 2.23 1.24 1.41
Cl.sup.- after 4 h (%) 1.97 2.31 1.26 1.43 Cl.sup.- after 24 h (%)
1.97 gelled 1.27 gelled Level of organically 0.87 -- 0.42 bonded
chlorine (%) based on solution* Shelf life at >10 days 1.5 h
>10 days 3 h 50.degree. C.
______________________________________ *after 24 h
This Table shows that the products obtained by 4c/5c lead to a
decrease in the organically bound chlorine content (increase in
Cl.sup.-), but do not have a sufficiently long shelf life (gel
formation after 24 h).
By contrast, the products obtained by 4b/5b are still stable after
10 days (50.degree. C.). However, the increase in the Cl.sup.-
content is distinctly less than that in the resins according to the
invention. In the case of resin (5b) the level of organically bound
chlorine comes out as 0.42%; in Examples 6, 7 and 8 according to
the invention, the level of organically bound chlorine is lower
than this value.
These experiments show that the process described in U.S. Pat. No.
3,352,833 does not give stable products low in organically bound
chlorine as are provided by the process according to the invention.
This confirms what is known from the prior art. The processing of
alkali-activated resins must take place with accurate alkali
metering within a certain period, which is felt to be a
considerable disadvantage in practice.
* * * * *